The present disclosure relates generally to the field of computer systems and, more particularly, to a microprocessor retention system.
As computer systems grow in speed and shrink in size, issues of heat dissipation and component spacing in the interior of the computer system become more important. Microprocessors generate excessive amounts of heat. The heat generated by a microprocessor is especially problematic in multiple processor systems, including many server systems, in which multiple processors are located on a single motherboard. Because most microprocessors do not have a physical structure to remove the heat generated by the microprocessor, many computer systems include a heat sink that is placed near the microprocessor to dissipate the heat generated by the microprocessor. Heat sinks are used to draw heat away from the microprocessor and the motherboard. To be most effective in dissipating heat generated by the microprocessor, a heat sink must be placed in close proximity to the surface of the microprocessor package. Even though the heat sink is placed in close proximity to the microprocessor, an air void may exist, and a thermally conductive medium in a solid or a liquid state must be physically placed between the heat sink and the microprocessor. The thermally conductive heat transfer medium minimizes the thermal resistance between the microprocessor and heat sink, allowing the heat sink more quickly draw heat away from the associated microprocessor.
Within the chassis of the computer system, microprocessor retention systems are used to maintain the position of the heat sink relative to the microprocessor. In some designs, each microprocessor is mounted individually to the printed circuit board and chassis. The practice of individually mounting of each microprocessor and associated heat sink raises several difficulties in the design and assembly of the motherboard of a computer system. Mounting each microprocessor individually on the motherboards consumes an excessive amount of space on the motherboard. Individually mounting each microprocessor involves mounting each microprocessor with its accompanying retainers and clips. As such, mounting each microprocessors in this way consumes a large amount of the limited space on the motherboard and does not take into account the economies of space afforded by mounting multiple processors as part of a single microprocessor retention system. In addition, a number of screws or other attachments must be used for each individual retention system. The use of a number of individual screws for each processor causes delays or extends the production time of each computer system. Moreover, each time that a screw is affixed to the printed circuit board or chassis of the computer system, there is a possibility that a manufacturing error will damage the printed circuit board of the computer system.
Second, mounting the microprocessor retention system to the metal chassis of the computer system causes difficulties in servicing and assembling the computer system. First, mounting a bracket or retainer of the retention system to the chassis of the computer system makes servicing or replacing the microprocessor difficult and time consuming. To service or replace the microprocessor, the retention system, in some cases, must be disconnected from its attachment to both the motherboard and the chassis of the computer system. Second, attaching a microprocessor retention system to the chassis of the computer system necessarily creates another connection point between the printed circuit board and the chassis of the computer system. In some computer systems, motherboards are mounted to the chassis of the computer system by a toolless attachment, allowing the motherboard to be easily installed in and removed from the chassis of the computer system. Mounting a microprocessor retention system to the chassis, however, eliminates this toolless removal feature in that an additional connection point is established between the motherboard and the chassis of the computer system.
The microprocessor retention system of the present disclosure includes a base with a plurality of slots formed in the base for receiving a plurality of microprocessors and associated heat sinks. Each heat sink is placed on top of a microprocessor. A thermally conductive layer may be placed between the heat sink and the microprocessor. The retention system includes a cover that includes in the cover a number of springs positioned along the sides of the cover. Each heat sink is in contact with two springs of the cover of the retention system. When the cover is secured in place over the base of the retention system, the springs are compressed, resulting in the application of a compressive force to the base of the heat sink. The heat sink in turn applies a compressive force to the microprocessor, placing the microprocessor and heat sink in thermal contact, either directly or through a thermally conductive layer placed between the microprocessor and heat sink. The cover is secured over the base of the retention system by a latch mechanism coupled to the cover of the base. The latch includes hooks that engage pins in the base of the retention system. When the hooks are engaged, the springs of the cover are compressed on the base of the heat sinks.
The microprocessor retention system of the present disclosure is advantageous in that it provides a spring-loaded thermal contact between the microprocessor or microprocessors of the computer system and their associated heat sinks. When the cover of the retention system is engaged in place, the heat sinks of the retention system are held firmly against the microprocessors of the retention system, minimizing the thermal flow from the microprocessor to the heat sink. Another advantage of the retention system of the present disclosure is a retention system that does not require an attachment to the chassis of the computer system. Rather, the retention system of the present disclosure may be coupled only to the motherboard of the computer system through a minimal number of screws or other attachments.
In addition, the microprocessor retention system disclosed herein is advantageous in that the structure of the base and cover of the system provides a cover for the passage of air over and through the fins of the heat sinks of the system. Once assembled, the retention system is bounded on four sides, created a plenum for the passage of air over the heat sinks, thereby improving the ability of the retention system to dissipate heat generated by the microprocessors of the system.
Another advantage of the present invention is a latch mechanism on the cover of the system that latches the cover of the system in place on the basis while applying a relatively uniform force to the springs and heat sinks of the retention system. Another advantage of the present invention is that the arrangement of the springs and heat sinks of the retention system provides for a uniform compressive force across the base of the heat sinks. The springs of the retention system may be curved in shape, causing the springs to become bowed when a compressive force is applied to the spring. When the spring is bowed, much of the surface area of the springs is placed in contact with the surface area of the base of the heat sink, resulting in the application of a firm, uniform compressive force across the surface of the heat sinks and the respective microprocessors.